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![]() "Milton Waddams" wrote in message ... Which is more accurate to use in estimating leeway, the true wind/current or the apparent wind/current? When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard |
#2
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![]() "Wilbur Hubbard" wrote in message ... When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard Im not so sure about that... leeway can be estimated on many levels.... the fellow out in a motor dinghy, another guy out in a sailing dinghy, and the person out in a larger yacht with navigation instruments on board. estimating leeway in a harbour is entirely a different matter from estimating it in the open ocean. leeway is also something that varies a lot with the type of vessel. I know when im out sailing in sydney harbour on my beach cat, i suffer leeway a lot, but i can eye it in off a landmark to allow for my course. I know in relaity i will be lucky to end up with a course made good within 30 degrees of what i was helming for! Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it sure can add up to a lot! If im out of sight of land it gets to be impossible for me to estimate in my head and then its time to compare on a chart my GPS course vs. compass steered course. It would take a very experienced and/or lucky person to be able to estimate leeway on a vessel they were unfamiliar with in waters that were unknown to them. Shaun |
#3
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![]() "Shaun Van Poecke" wrote in message ... "Wilbur Hubbard" wrote in message ... When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard Im not so sure about that... leeway can be estimated on many levels.... the fellow out in a motor dinghy, another guy out in a sailing dinghy, and the person out in a larger yacht with navigation instruments on board. estimating leeway in a harbour is entirely a different matter from estimating it in the open ocean. leeway is also something that varies a lot with the type of vessel. I know when im out sailing in sydney harbour on my beach cat, i suffer leeway a lot, but i can eye it in off a landmark to allow for my course. I know in relaity i will be lucky to end up with a course made good within 30 degrees of what i was helming for! Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it sure can add up to a lot! If im out of sight of land it gets to be impossible for me to estimate in my head and then its time to compare on a chart my GPS course vs. compass steered course. It would take a very experienced and/or lucky person to be able to estimate leeway on a vessel they were unfamiliar with in waters that were unknown to them. Shaun Over here in the U.S.A. we have something called waasGPS. It's a great invention. It's accurate to within inches. You set a course to where you wish to arrive at. Then you follow the compass course on the screen on the GPS. But if you have any leeway, drift or set the GPS comes up with something called cross-track error and it tells you which way to steer to get back on course. The cross-track error is a combination of set, drift and leeway. It's not possible to tell them apart. It's a combination figure only. What matters is you know your position on the chart and you've corrected for any and all deviations from the course line. So, and I hate to say it, Milton Waddams is asking a silly question. The people who are trying to sound like some kind of authority figures are making fools out of themselves. Wilbur Hubbard |
#4
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Wilbur Hubbard wrote:
"Shaun Van Poecke" wrote in message ... "Wilbur Hubbard" wrote in message ... When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard Im not so sure about that... leeway can be estimated on many levels.... the fellow out in a motor dinghy, another guy out in a sailing dinghy, and the person out in a larger yacht with navigation instruments on board. estimating leeway in a harbour is entirely a different matter from estimating it in the open ocean. leeway is also something that varies a lot with the type of vessel. I know when im out sailing in sydney harbour on my beach cat, i suffer leeway a lot, but i can eye it in off a landmark to allow for my course. I know in relaity i will be lucky to end up with a course made good within 30 degrees of what i was helming for! Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it sure can add up to a lot! If im out of sight of land it gets to be impossible for me to estimate in my head and then its time to compare on a chart my GPS course vs. compass steered course. It would take a very experienced and/or lucky person to be able to estimate leeway on a vessel they were unfamiliar with in waters that were unknown to them. Shaun Over here in the U.S.A. we have something called waasGPS. It's a great invention. It's accurate to within inches. You set a course to where you wish to arrive at. Then you follow the compass course on the screen on the GPS. But if you have any leeway, drift or set the GPS comes up with something called cross-track error and it tells you which way to steer to get back on course. The cross-track error is a combination of set, drift and leeway. It's not possible to tell them apart. It's a combination figure only. What matters is you know your position on the chart and you've corrected for any and all deviations from the course line. So, and I hate to say it, Milton Waddams is asking a silly question. The people who are trying to sound like some kind of authority figures are making fools out of themselves. Wilbur Hubbard And then the satellite gets shot out of the sky when you're in the middle of the Gulf Stream.... |
#5
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![]() "Wilbur Hubbard" wrote in message ... "Shaun Van Poecke" wrote in message ... "Wilbur Hubbard" wrote in message ... When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard Im not so sure about that... leeway can be estimated on many levels.... the fellow out in a motor dinghy, another guy out in a sailing dinghy, and the person out in a larger yacht with navigation instruments on board. estimating leeway in a harbour is entirely a different matter from estimating it in the open ocean. leeway is also something that varies a lot with the type of vessel. I know when im out sailing in sydney harbour on my beach cat, i suffer leeway a lot, but i can eye it in off a landmark to allow for my course. I know in relaity i will be lucky to end up with a course made good within 30 degrees of what i was helming for! Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it sure can add up to a lot! If im out of sight of land it gets to be impossible for me to estimate in my head and then its time to compare on a chart my GPS course vs. compass steered course. It would take a very experienced and/or lucky person to be able to estimate leeway on a vessel they were unfamiliar with in waters that were unknown to them. Shaun Over here in the U.S.A. we have something called waasGPS. It's a great invention. It's accurate to within inches. You set a course to where you wish to arrive at. Then you follow the compass course on the screen on the GPS. But if you have any leeway, drift or set the GPS comes up with something called cross-track error and it tells you which way to steer to get back on course. The cross-track error is a combination of set, drift and leeway. It's not possible to tell them apart. It's a combination figure only. What matters is you know your position on the chart and you've corrected for any and all deviations from the course line. So, and I hate to say it, Milton Waddams is asking a silly question. The people who are trying to sound like some kind of authority figures are making fools out of themselves. Wilbur Hubbard There's no such thing as a silly question. And, the people answering his question are just being helpful. Hey, does this Wilbur Hubbard sound a little like Bobsprit? Harry Harris -- Posted via a free Usenet account from http://www.teranews.com |
#6
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Charlie Morgan wrote:
On Wed, 21 Feb 2007 12:26:28 -0500, katy wrote: Wilbur Hubbard wrote: "Shaun Van Poecke" wrote in message ... "Wilbur Hubbard" wrote in message ... When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard Im not so sure about that... leeway can be estimated on many levels.... the fellow out in a motor dinghy, another guy out in a sailing dinghy, and the person out in a larger yacht with navigation instruments on board. estimating leeway in a harbour is entirely a different matter from estimating it in the open ocean. leeway is also something that varies a lot with the type of vessel. I know when im out sailing in sydney harbour on my beach cat, i suffer leeway a lot, but i can eye it in off a landmark to allow for my course. I know in relaity i will be lucky to end up with a course made good within 30 degrees of what i was helming for! Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it sure can add up to a lot! If im out of sight of land it gets to be impossible for me to estimate in my head and then its time to compare on a chart my GPS course vs. compass steered course. It would take a very experienced and/or lucky person to be able to estimate leeway on a vessel they were unfamiliar with in waters that were unknown to them. Shaun Over here in the U.S.A. we have something called waasGPS. It's a great invention. It's accurate to within inches. You set a course to where you wish to arrive at. Then you follow the compass course on the screen on the GPS. But if you have any leeway, drift or set the GPS comes up with something called cross-track error and it tells you which way to steer to get back on course. The cross-track error is a combination of set, drift and leeway. It's not possible to tell them apart. It's a combination figure only. What matters is you know your position on the chart and you've corrected for any and all deviations from the course line. So, and I hate to say it, Milton Waddams is asking a silly question. The people who are trying to sound like some kind of authority figures are making fools out of themselves. Wilbur Hubbard And then the satellite gets shot out of the sky when you're in the middle of the Gulf Stream.... All 30 of them? CWM Just the one you're using...or 2 or 3 or whatever...the point, so obviously missed by your limited mind, is that GPS systems rely on other devices that could prove unreliable...or unavailable... |
#7
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Harry Harris wrote:
"Wilbur Hubbard" wrote in message ... "Shaun Van Poecke" wrote in message ... "Wilbur Hubbard" wrote in message ... When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard Im not so sure about that... leeway can be estimated on many levels.... the fellow out in a motor dinghy, another guy out in a sailing dinghy, and the person out in a larger yacht with navigation instruments on board. estimating leeway in a harbour is entirely a different matter from estimating it in the open ocean. leeway is also something that varies a lot with the type of vessel. I know when im out sailing in sydney harbour on my beach cat, i suffer leeway a lot, but i can eye it in off a landmark to allow for my course. I know in relaity i will be lucky to end up with a course made good within 30 degrees of what i was helming for! Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it sure can add up to a lot! If im out of sight of land it gets to be impossible for me to estimate in my head and then its time to compare on a chart my GPS course vs. compass steered course. It would take a very experienced and/or lucky person to be able to estimate leeway on a vessel they were unfamiliar with in waters that were unknown to them. Shaun Over here in the U.S.A. we have something called waasGPS. It's a great invention. It's accurate to within inches. You set a course to where you wish to arrive at. Then you follow the compass course on the screen on the GPS. But if you have any leeway, drift or set the GPS comes up with something called cross-track error and it tells you which way to steer to get back on course. The cross-track error is a combination of set, drift and leeway. It's not possible to tell them apart. It's a combination figure only. What matters is you know your position on the chart and you've corrected for any and all deviations from the course line. So, and I hate to say it, Milton Waddams is asking a silly question. The people who are trying to sound like some kind of authority figures are making fools out of themselves. Wilbur Hubbard There's no such thing as a silly question. And, the people answering his question are just being helpful. Hey, does this Wilbur Hubbard sound a little like Bobsprit? Harry Harris No. |
#8
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Charlie Morgan wrote:
On Wed, 21 Feb 2007 15:25:10 -0500, katy wrote: Charlie Morgan wrote: On Wed, 21 Feb 2007 12:26:28 -0500, katy wrote: Wilbur Hubbard wrote: "Shaun Van Poecke" wrote in message ... "Wilbur Hubbard" wrote in message ... When you estimate leeway you end up plotting it on a chart, don't you? That should tell you something. On a chart there's no apparent wind and there's no apparent current. There is only true wind and true current as it applies to the chart. If you used apparent wind/current you'd have to extrapolate to true prior to placing yourself on the chart. So why bother? Leeway is a function of true wind and current when it comes to plotting your position on a chart. Apparent is totally meaningless because you have to ask yourself the burning question: apparent to what? Your ship, of course. What you feel from the deck of your ship means nothing as concerns your geographical position (GP) Wilbur Hubbard Im not so sure about that... leeway can be estimated on many levels.... the fellow out in a motor dinghy, another guy out in a sailing dinghy, and the person out in a larger yacht with navigation instruments on board. estimating leeway in a harbour is entirely a different matter from estimating it in the open ocean. leeway is also something that varies a lot with the type of vessel. I know when im out sailing in sydney harbour on my beach cat, i suffer leeway a lot, but i can eye it in off a landmark to allow for my course. I know in relaity i will be lucky to end up with a course made good within 30 degrees of what i was helming for! Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it sure can add up to a lot! If im out of sight of land it gets to be impossible for me to estimate in my head and then its time to compare on a chart my GPS course vs. compass steered course. It would take a very experienced and/or lucky person to be able to estimate leeway on a vessel they were unfamiliar with in waters that were unknown to them. Shaun Over here in the U.S.A. we have something called waasGPS. It's a great invention. It's accurate to within inches. You set a course to where you wish to arrive at. Then you follow the compass course on the screen on the GPS. But if you have any leeway, drift or set the GPS comes up with something called cross-track error and it tells you which way to steer to get back on course. The cross-track error is a combination of set, drift and leeway. It's not possible to tell them apart. It's a combination figure only. What matters is you know your position on the chart and you've corrected for any and all deviations from the course line. So, and I hate to say it, Milton Waddams is asking a silly question. The people who are trying to sound like some kind of authority figures are making fools out of themselves. Wilbur Hubbard And then the satellite gets shot out of the sky when you're in the middle of the Gulf Stream.... All 30 of them? CWM Just the one you're using...or 2 or 3 or whatever...the point, so obviously missed by your limited mind, is that GPS systems rely on other devices that could prove unreliable...or unavailable... You could just as easily break your compass, lose your paper charts overboard or a variety of other mishaps that are at LEAST as likely to happen as your fantasy about the satellites. Then again, your rudder could break, your mast could come down... GPS satellites being shot down seems very unlikely compared to the frequency of mishaps that actually DO happen. What if Magnetic North suddenly moves? CWM Satellites shut down all the time...you must be a very clumsy person if you lose all your stuff overboard like that...how many screwdrivers live under the hull of your boat? |
#9
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![]() "Charlie Morgan" wrote in message You could just as easily break your compass, lose your paper charts overboard or a variety of other mishaps that are at LEAST as likely to happen as your fantasy about the satellites. Ah, you saw Captain Ron, didn't ya. GPS satellites being shot down seems very unlikely compared to the frequency of mishaps that actually DO happen. Far less likely than the other things you mentioned, obviously. Not to mention the fact that virtually every country on Earth uses *our* GPS train of satellites. What if Magnetic North suddenly moves? It moves every minute of the day, fortunately not very far. Max |
#10
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katy wrote:
.... And then the satellite gets shot out of the sky when you're in the middle of the Gulf Stream.... All 30 of them? CWM Just the one you're using...or 2 or 3 or whatever...the point, so obviously missed by your limited mind, is that GPS systems rely on other devices that could prove unreliable...or unavailable... You could just as easily break your compass, lose your paper charts overboard or a variety of other mishaps that are at LEAST as likely to happen as your fantasy about the satellites. Then again, your rudder could break, your mast could come down... GPS satellites being shot down seems very unlikely compared to the frequency of mishaps that actually DO happen. What if Magnetic North suddenly moves? CWM Satellites shut down all the time...you must be a very clumsy person if you lose all your stuff overboard like that...how many screwdrivers live under the hull of your boat? I don't know why the issue of satellites failing always comes up. The birds go offline all the time and no one notices. Far more likely to cause a problem is the on board GPS. The ship's power can go out, the cable can fall off, the batteries can die, the antennae can get kicked by a clumsy crew. Any of these things can happens, and if Murphy has his way, it will happen just when the fog comes in while you're crossing Vineyard Sound with a 3 knot cross current and numerous ferry boats. |
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